Background

Radiotherapy techniques in the treatment of breast cancer are continuing to evolve

The American College of Radiology (ACR), Quality Research in Radiation Oncology (QRRO) periodically surveys US radiation facilities regarding use of various technologies and techniques employed for radiation planning and delivery.

Prior survey QRRO results in 1999 found CT based planning to be employed in 22% of cases

In 2007, the QRRO survey again evaluated the quality of breast cancer treatment planning and delivery and documented integration of newer radiation methods since its last survey in 1999. These results are presented here.

Materials and Methods

QRRO used a two-staged stratified random sample to perform a national survey of the treatment of operable breast cancer patients in 2007 in the USA

There were 1879 radiation facilities nationally in 4 strata;126 institutions were randomly selected and invited; 42 accepted the survey

Each facility provided their list of patients treated and this yielded 412 cases from 42 randomly institutions.

Multi-leaf collimation (MLC) was the most common form of beam modifier used, followed by physical (30%) then dynamic wedges (19%).

For the 27 PBI cases, 10 were treated brachytherapy, seven were treated with 3DCRT

100% had a CT based plan and 78% had a DVH present.

All met requirements for the prescription dose to cover 90% of PTV

Skin toxicity was assessed weekly in 89%

dry desquamation occurred in 38%; moist 13%

57.8% had either dry or moist desquamation; there was more moist desquamation in 3D than IMRT based plans

The rate for any desquamation for 3DCRT methods was 52%, 52% for IMRT, and all other 71% (p = 0.125).

Breast pain occurred in 40%.

IMRT is more common in small non academic centers in the Northeast USA

Author's Conclusions

ACR QRRO documents change in the technical delivery of RT for breast cancer as of 2007 compared to 1999, when CT planning and conformal methods were uncommonly used.

3DCRT/IMRT methods are now predominant

Contoured CT volumes are normally done, but there is less documentation of DVH for plan analysis than would be predicted

Clinical Implications

Nearly all breast cancer treatment now is CT based. This allows more accurate assessment of dose distribution than 2D planning. It is unclear why there were situations where contours were done but corresponding DVHs were not, but this may be a reflection of the continued use of traditional 2D parameters in 3D planning (such as measuring the number of centimeters of lung in a tangent field or prescribing a SC field to a depth of 3 cm).

3D CRT is the most common technique employed, but IMRT and PBI use is increasing.

While the use of IMRT did not appear to have a significant effect on acute skin toxicity, the impact of use of IMRT on other clinical outcomes and its impact on dosimetric parameters were not assessed.

The use of IMRT also varies depending on facility and geography. The lower use of IMRT within academic practices as compared to small private practices suggests that economic considerations may influence decisions about radiation technique, but a more detailed questionnaire specifically asking what factors play into the use of IMRT would be useful in drawing more firm conclusions.